The present invention relates generally to textile machines of the type used for wet processing of textile fabric in continuous cloth rope form and to methods of wet processing textile fabrics utilizing such machines.
Textile wet processing machines have long been utilized in the textile industry for piece dyeing of textile fabrics in endless cloth rope form. In machines of this type, e.g., jet dyeing machines, the endless fabric rope is circulated through a processing chamber containing a treating liquid, wherein the cloth rope is formed in a plaited plug form. The cloth plug advances through the treating chamber by continuous drawing off of the leading end of the plug and conveyance thereof to the trailing end of the plug, commonly accomplished by means of a fabric lifting reel and a downstream jet of the textile treating liquid.
A common form of treating chamber utilized in such textile wet processing machines is of a U-shape defined by a pair of laterally spaced U-shaped side walls joined at their outer edges by a U-shaped transverse wall. The chamber is situated in the bottom of the treating vessel, the side walls typically being perforated to permit flow of the treating liquid therethrough between the interior of the chamber and the bottom liquid containment area of the vessel. It is also common to provide an inner transverse wall between the inner edges of the perforated side walls to maintain the fabric plug at least partially submerged in the treating liquid within the vessel, the inner wall typically extending substantially the full extent of the chamber for such purpose.
Disadvantageously, however, the provision of a treating chamber with an inner wall restricts the chamber to a defined volume which may limit the flexibility of the wet processing machine for treating different types of fabrics or for treating different lengths of a given fabric. One function of the inner wall is to define the plug form of the cloth rope. As will be understood, fabrics having different characteristics, e.g., different thicknesses and weight per yard, will behave differently in the wet processing machine and therefore may require a treating chamber of differing volumetric size in order to enable the machine to realize its maximum capacity for treating the individual fabric. However, when the treating chamber has a fixed inner wall, the capacity of the machine for processing thicker and heavier fabrics may be limited thereby. Conversely, the machine may be less than optimally effective for treating lighter weight fabrics for which a treating chamber of relatively smaller volume would be preferred.
One solution which has proved effective to overcome the above-described disadvantages is disclosed in U.S. Pat. No. 5,014,526, the invention of which provides an inner wall having lateral flanges for mounting by special fasteners in differing dispositions between the side walls of the U-shaped chamber of such wet processing machines, utilizing the existing perforations in the side walls to selectively vary the cross-sectional size of the chamber so as to accommodate particular processing requirements of different fabrics.
However, one additional disadvantage not addressed by the invention of U.S. Pat. No. 5,014,526 is that, with any given type of fabric, the lengthwise extent of the fabric which will be maintained in plug form within the chamber will be a function of the total overall length of the fabric rope being processed. Since the inner wall will tend to present an additional source of friction retarding advancing movement of the fabric plug through the chamber, the plug formed when processing shorter lengths of fabric will tend to reside primarily within the entrance end of the chamber and, hence, the inner wall may impair the ability of the lifter reel to freely withdraw the fabric from the leading end of the plug.
Another aspect of the operation of textile wet processing machines of the aforedescribed type which has received considerable attention in recent years is the overall elapsed time required to complete the processing of a given fabric rope. A fundamental objective in improving wet processing machines and advancing the technology of wet processing methodology is to reduce the average processing time without negatively affecting fabric quality. Various parameters of the basic wet processing operation of such machines are recognized to affect overall processing time, two basic factors for any given type of fabric being the length of the fabric rope and the traveling speed of the fabric through the machine which, in turn, determines the time required for the entire length of the fabric rope to make one complete circulation through the machine. To a significant extent, the traveling speed of the fabric is determined by the combined effect of the fabric lifting reel and the liquid impingement action of the downstream liquid jet on the fabric, which collectively serve to transport the fabric so as to maintain its circulating motion through the processing chamber. With regard to the liquid jet itself, the mechanical arrangement of the jet structure, i.e., the size of the liquid jet gap and the overall flow capacity of the jet in conjunction with the associated liquid pump supplying the processing liquid to the jet, determines the manner and force with which the jetted liquid impinges and entrains the fabric and, in turn, attention has been directed to refinement and improvement of the structure and operation of liquid jets to accommodate more rapid transport of fabrics without negatively affecting the liquid interaction with the fabric as well as to accommodate use with a variety of differing fabrics.
Efforts have also been directed to increasing the capacity of processing machines without increasing processing time. Toward this end, experimentation has been conducted with running two lengths of textile fabric simultaneously through the same treating chamber, lifting reel and liquid impinging jet. One possibility contemplated is a so-called "piggyback" operation wherein one length of fabric is transported in conventional fashion in an endless rope form with a leading end of the second length of fabric being sewn to the first fabric rope and allowed to extend therefrom in trailing relation more or less side-by-side with the fabric rope with the opposite end of the second fabric being left unattached. An alternative possibility is to operate the machine with two independent endless fabric ropes circulating through the machine in side-by-side relation without any attachment between the two ropes. In each case, problems have been encountered with the two fabrics becoming twisted or looped with respect to one another which have prevented commercially satisfactory and effective use of these techniques.